Improvement in air-pumps for steam-engines



UNITED STATES VPATENT OFFICE.

DANIEL A. IVOODBURY, OF ROCHESTER, NEIV YORK.

IMPROVEMENTIN AIR-PUMPS FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 28,229, dated May S,1860.

To a/ZZ wton it may concern:

Be it known that I, DANIEL A. WOODBUEY, of Rochester, in the county ofMonroe and State of New York, have invented anew and useful Improvementin Air-Pumps for Condensing Steam-Engines; and I do hereby declare thatthe following is a full, clear, and exact description of the same,reference being had to the accompanying drawings, forming part of thisspecification, in which- Figure l is a longitudinal section of anairpump with my improvement. Eig. 2 exhibits a modification of thepiston.

Similar letters of reference indicate corresponding parts in the twoiigures.

The object of my invention is to enable the air-pump ofacondensing-engine to be worked at as high a rate of speed as it isdesirable to work the engine without producing the concussions whichattend the working of the airpumps in common use for such engines, andwhich are more or less violent, according to the speed of the engine;and to this end my invention consists in the employment in such anair-pump of a piston or plunger elongated at one or both ends,substantially as hereinafter described, whereby both water and air arecaused to be discharged simultaneously from the commencement of thestroke and sufficient air is retained to serve as a cushion to thepiston to the end of the stroke.

My invention also consists in a certain arrangement of the passages andvalves whereby the simultaneous discharge of water and air is providedfor.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and operation.

A is the cylinder or barrel of the pump, having its head B and bottom Cmade of conical form.

D is the piston, made either solid or hollow, but without apassagethrough it, fitted to the cylinder A with packing c in the usual manner,and elongated at both ends, as shown at d CZ, in a conical formcorresponding with the form of the top and bottom of the cylinder. Thiselongation of the piston should preferably be such that its lower endwill never -leave the water in the cylinder.

E is a valve-chest secured to or cast on one side of the cylinder andextending nearly the whole length thereof, divided into threevalvechambers F G II, each fitted with double valves of vulcanizedindia-rubber. Thevalveports b b of the lower chamber F communicate withthe receiving-chamber I, to which the receiving-pipe- K from thecondenser is,

has communication by its valve-portsf f with a passage g, which forms acommunication between the middle chamber G and the upper part of thecylinder. The passages c and g communicate with the cylinder at the endsof its parallel bore, in which the piston works tightly.

In the operation of this pump the bottom of f the piston enters thewater so gradually that it produces no concussion, even if it be not somuch elongated that its lower extremity will never entirely leave thewater, and the water rnd air are discharged simultaneously, and aportion of the air is retained in the cylinder throughout both the upand down strokes, except just at the close of the latter, when it isexpelled by the piston passing the upper edge c of the opening c; but asthe descent of the piston has then almost ceased andthe passage of theair ceases very gradually no concussion is produced by the continueddescent, and hence the piston is practically perfectly cushioned withair, and yet all the airis expelled from the lower part of thepump-cylinder. A small quantity of air is, however, always retained inthe upperpart of the cylinder, owing to the clearance necessarilyallowed between the piston and the head B; but this is not essential, asthe upper part of the pump is only auxiliary to the lower and might bedispensed with; but the pump works better with it.

By the simultaneous discharge of the water and air as affected by theelongation ot' the piston a great advantage is obtained over thedischarge of the air first and the water afterward in the reliefaiforded to the valves by the more gradual discharge of the waterconsequent upon its discharge through the whole stroke. In the downwardstroke of the piston,with the arrangement of valves receiving-chamber I,valve-ports b b', cham- Y ber F, and passage c, and leave the upper partof the cylinder by the passage g, ports f f',

chamber H, and pipe J. Instead of elongating the piston in the conicalform represented in Fig. l, it may be elongated in the cylindrical formshown at i in Fig. 2; but the conical form is preferable, as it effectsa more gradual discharge of the air.

By this improvement I have succeeded in working a condensing-engine atone hundred and fifty strokes per minute without any perceptibleconcussion or other objectionable effects, the air-pump working at thesame velocity, while with the ordinarily-constructed air-pumps aconcussion is very perceptible in engines workingas slowly as twentystrokes per minute. This capability of working at a high Velocity makesthe invention of immense advantage for propeller and mill engines.

What I claim as my invention, and desire to secure by Letters Patent,is-

l. The elongation of the piston of the airpump at one or both ends,substantially as herein specified, tov produce the results herein setforth.

2. The arrangement of `the 4three valve-A chambers, the valves,valve-ports, and passages, substantially as and for the purpose hereinset forth. l

D. A. WOODBURY. Witnesses:

Y Y. JAMES HOLZLAND, MARTIN BRIGGs.

